1 ounce whole dried cayenne chili peppers or crushed red pepper flakes (about 3 tablespoons)
1 tablespoon red wine vinegar
1 small garlic clove, peeled
3/4 teaspoon salt
1/2 teaspoon sweet or smoked paprika (not hot)
1/4 teaspoon sugar
1/4 teaspoon freshly ground black pepper
1/2 cup olive oil
In a small bowl or pot, cover chili peppers or flakes with boiling water and let soak 30 minutes. Drain. If using whole chilies, remove stems and seeds.
Transfer to blender or small food processor. Add vinegar, garlic, salt, paprika, sugar and pepper, and blend well to finely chop chilies. Add oil, and blend to emulsify.
Taste and adjust seasoning with vinegar, salt and pepper; harissa should be quite spicy and thin enough to pour. Serve immediately or refrigerate, tightly covered, up to 1 week.